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June 11, 1929. E. J. MISSIEN 1.716.789

METHOD OF AND MEANS FOR CONTROLLING RECIPROCATING MOTORS Filed March 5,1924 2 Sheets-Sheet 1 INVENTOR June 11, 19 E. J. MISSIEN METHOD OF ANDMEANS FOR CONTROLLING RECIPROCATING MOTORS Filed March 5, 1924 2Sheets-Sheet 2 INVENTOR Patented June 11, 1929.

' F A TES P T.

1,716,789 E-NT oFFicE.

EDWARD .J l' hli siiEN OFEEfIITSBURGiH, VI-IELNNSYLIVANIA, ASSIGNOR TOCENTRAL ELECTltIC TooLeQ rANY, A CQRPORATION or PENNSYLVANIA v A ND MEANS FOR CONTROLLING RECIPROCATING MOTORS.

This a pplication is{continued part from "application Serial No,"414,520"filed Feb-' ru'aryj 1'2, '192 1,relating to electric mechanism, and inpart'from applicat'ion' Serial to 'rnet h'od's of operating electric;tools.

: My" invention rel'at'es to electromagnets 5 and means foretintrdlli'ng 5 the sa me, -and particularly cc e l c'trdr'fia'gn ts omrising a I fmovableelement tha 'c'urrent' supplied to the electromagnetin ac-- cordance -iyithf-tl i of the electro of control involvedissusceptible? of -ap'pli-- V the-hammer winding caused by themovecation for 'cdnti olling 'electrtimagnet's' applied -'to', oremployed for other purposes or uses.

My invention provide's a;- novel 'system' for the voltage across thecircuit or the current controlling a reciprocatingmotor? In operatingelectric hammers of the type n which aneleetromagnet'is per odicallyenergized to reciprocate its core' member- 3.; againstatoo'lor"other-device to fdofuseful work, eurr'ent controlling switchingdevices, such as mechanicalvibrators,"have been em-' ployed, embodyingrelatively fm(iv-able I contacts i' ir," iii. 1 'f ::'''r I--.

VVhet-her direct current or alternating currentcnergy-is' used tooperate the 'hammer, 1t is'desira'hle to'control the operation of theswitching device'in accordance with the-op eration of the l1a1nmeri*"lheswitching 'de-" vices may thus be controlled' to operate at optimuminstants, that is, at instants beyond which continuedenergization-of theharmmer is not desired, or at-instants of min iinum circuit current, aszero current values when alternating current 'energyi's' used? Inorderto operate a motoi of the reciprocating :type, it *is necessary;to=supply energy'to the motor in the form of impulses. Alternatingcurrent energy, which is de- -rivable from the usual commmsial. lightand tion 'in order' that driven drum t 'i's' em lo'yedto douse- Y I 'f'by the contacts. 2- invention is to l-prdvide f shall constitute a Myinvention has a mrticulari application Applicatio'n filed March 5,1924.' Serial No. 697,052.

power circuit, is adaptable for energizing a reciprocating motor butrequires rectificathe respective current; wares may be supplied to themotor as energy impulses.

Switching devices, Whether of the motor v ype or of the vibrating type,

after'having been once adjusted, will always operate' at the same time,irrespective of ex- 'ternal conditions in the-circuit controlled lV'henalternating current energy is used,

it is desirable to open the circuit. at instants or zero current inorder toreduce't-he arcing between contact members. In the usualrectifier there is considerable arcing between the contact members.-Such condition is aggravated by the varying inductive react- "ance inthe motorwindings caused by the movement of the movable core. VVhen the'corenioves smoothly in synchronism with the applied energy impulses,the arcing between the contacts is at-a minimum," but when the coremoves unevenly and leads or lags behind the energy impulsesfthe arcingis cons derably 111creased.- f;

Due'to the variations'ln the impedance of ment of the core, the contactswould open the circuit of the hammer winding-at times when conditionsobtaining in the circuit controlled by the contacts.

ItJis an object of my invention to control the operation of the contactsof acurrent controlling device in accordance with and in response toconditions in a circuit controlled -by the contacts.

Specifically, my object is to control the energization of anelectromagnet, particularly such as used as a reciprocating mot-or, byelectric, magnetic or electromagnetic conditions obtaining in the:elect-romagnet or motor; v

In pi'acticing myinvention I employ a mel-ereenting motor comprising anactuating tiontot the. actuating winding.

In the present application I use an .electromagnet arranged to-,0per{tte as ,a reciproeating ;motor to do uscfugl Qllk as a perveussive itool,- suoh as'an electric hammer, 'for drilling, chipping,,riveting, .etc. A switch- ..ing ,-devvice, in circuit w th .theactuating winding, periodically transmits an energy Himpulse-tohsaidWinding Ill-I161 establishes a reciprocating movement of the core,member .in synchronism. with .the transmitted Lunpulses. Byreguilatingwthe operation of the switehing devioe in accordance-with theelectromotiue iforceinduced in .the auxiliary .or

secondary mind;i ng,-the switchingdevice will be controlled in=accordancewith.the operation of. the leleotromagnet-or electric harm-3o:

mer. Arcing between contacts of the-switching-device wvill thenebyheconsiderably .di-

minished iwhene alternating c rrent en rgy is used, and-the switchingdevice .willbe operated atthe pro )er time when dircotcurrent energy isuse -F or a beitter. understanding of the invention, referenceniay behad to the accompanying drawings in which? I Fig. 1is'a=c1oss-sectionalview of an .elecbottom views,'in eleyation, of themagnetic *iClIQlll-t members employed 1n the hammer shown in'Fig. 1;

F igs. .5, 6 and 7 are diagrammatic .views of electric circuits forcontrolling the opera- -tion 'of the hammer in Fig-1 in accordance withmy invention; and

Fig. 8 is a graph illustrating the general form of the current impulsestransmitted to the hammer.

As illustrated in Figs. 1 and 2, an elec tric hammer 10 comprises a mainor actuating winding 11, a core member 12 respon sive thereto andcontrolled thereby to do useful .Work, and an auxiliary or secondarywinding 13 disposed ad acent the main wind-- ing 11 and the core 12,'t-obe influenced in accordance with the energization of the main winding-11and the movement of the core 12 The hammer further comprises a barrel orguide 14, of non-magnetic material, to retain the core in apredetermined path of movement. A wlura lit ofironlaminations 15 aredispose around the main winding .11 and adjacent .the barrel 1; .toprovide a short air gap within which the auxiliary winding ,l3-,isndisposed. A front end plate 16 is disposed on and secured to the front mnd .of the barrel :14: and accommodates a tool bushing 17 which holds atool 18 in'the path of travel .of the cone 12in its forward i r me 'Arbeki n pla an dmnd :20 integral therewith are secured :to the ,rear end.01 the .banrel 1A: and cooperate (there- .with ,to hold a springcontrol-led baqkstop or bumper 521- in position in {the .path (of t aveo he core .12 in ,its backwa momem m- An en los g shell r e singflr-surrounds the elect-romagnet structure 'anqlis held in position 'bythe ,front and the-back end plates 16 and 1-9, A trigger switch 23 isdisposed in the handle ofttheihammer ,and

tiating'and stopping operation of the harnmer.

As illustrated in Fig. 2, the laminations are disposed .in sets aroundthe barrel let mid extend radially ,thereigrom. Each set of\lanrinzrtions has an air gap between the .ends of the inner laminationsl5. AlLo-f the air gaps ,togetlier. cqnsti.tute an annular air gap whichis bridged or shunted by the core in its recipmcatingmovement.

Several of the inner laminations of each set anev provided .wvith tips.or tenons 24,415 illustrated in -;F igs.3- .and 4,, ,that fi-t tightlyinto .openihgsin the-barred 14 and serve. to lock the windings inposition.

In Fig. 5 energy for operating the hammer 10 is derived from a source ofenergy which may he adinect 101" .an alternating current circuit 25 andis supplied to the main winding 11 of the hammer through a switchingdevice :26 and a magnet switch 27. The magnetswitch is controlled by thetrigger switch 23 von the hammer.

The switching device 26 comprises aspring 2S, tending normally to holdthe switch contacts closed, and a winding 29, operating, whensufiiciently energized, to open the switch contacts. .The winding 29 isconnectedto the secondary or auxiliary winding 13 on the hammer and isenergized in accordance with the .elect-r-omotive force induced in thesecondary winding 13, to oper-ate the switch 26. A condenser 31 and ablow out coil 32 are provided to diminish arcing between the switchContacts.

lVhen operation of the hammer is desired, the trigger switch 23 isclosed. "The magnet switch 27 thereupon closes to connect the .mainhammer winding-11 to the circuit'25 1 through the switch 25=and theblowout coil 32. The core 12 is thereupon drawn toward is subject ,tocontrol by the operator i501 inithe force of the spring 28. The mainhammer winding is thereupon (lo-energized andthe core 12, by reason ofits kinetic energy continues its movement until it strikes the tool 18or the backstop 21, depending 'upon the direction in which it istravelling. If

the core strikes the tool, useful work is 'done thereby. If the corestrikes the backstop, its kinetic energy-is stored in the spring of thebackstop and restored to the core on its forward stroke.

After the core passes the air gap, the switch 26 having been opened todisconnect the main hammer winding, the secondary winding 13 of thehammer is tie-energized. The switch 26 is thereupon immediately reclosedby its spring 28 to reconnect the main winding 11 to the circuit. Thecore is r thereupon again actuated but in the opposite direction -andwhen it substantially shunts the air between the ends of thelaminations, the switch 26 is again opened to disconnect the mainwinding from the circuit by reason of the electromotive force induced intheauxiliary winding. The core is thus moved back and forth at afrequency depending uponthe frequency of operation of the switchingdevice 26.

The time element of the core and the time element of the switchingdevice 26 should be equal. That is, the time from the instant of maximumvoltage in thesecondary winding of the hammer, until the core is out ofthe air gap, mustbc equal to the time which clapscs between opening andreclosing-of the contacts of the switching device 26.

Such correspondence may be obtained by adjustment of the spring 28 tovary the time element of the switch device.

Reciprocatory motion of the core may thus be obtained by periodicallyenergizing and tie-energizing the primary or main winding of the hammerand utilizing the.

voltage induced in the secondary winding to operate or control a switchor other device for controlling the energization and deenergization ofthe primaryor main winding.

By reason of the inductive relation of the main and the auxiliarywindings of the hammer and the magnetic circuits associated therewith, atransforn'ieraction exists when the main winding is energized. Only arela-.

tively small electromotive force, however, is induced in the auxiliarywinding when the main windingis energized, until the; core approachesthe air gap. At that time, more efficient transformer action occurs andthe induced electromotive force increases rapidly to a largevalue,whichissufiicient to operate the switch 26. l

The operation of the hammerconstitutes,

in effect, a series of operations as an electro-:

magnet. After' each operation has -'been effected the circuit of theoperating winding is momentarily opened to tie-energize the winding. Bymeans of the electromot-ive force induced 'inthe auxiliary winding, the

'formance'of each operation; that .is,'-the movement of: the core inonedirecti'on-or the other. 'Such -induced electroinotive force may beutilized for a useful purposeto indicate the operation oft-he hammer orto regulate its operation, as is herein described,'by controlling anexternal current-transmitting device. 1 r

I have disposed the auxiliary winding ad jacent the air gap although itmay be disposed in otherpositions inwhichit. will-be influenced by'themagnetic flux developed by the main windingi -In the'airgap theauxiliary-winding appears tobeamost responsive to the fiuxvai iationsefiect'ed by thecore-in its movement. c

In Figure 6 a modified i-rcuit is diagrammatically showh-,: similarto't-hat 'in-Fi'g. 5, except that a'switching' rdevice 40, ditferent Iin design, is -employed instead 5 of the switch device 26-ofi-tliesystem in Fig. 55. 5""

The .switch-dev-ice 40, of-Fig. 6, comprises in addition to the I switchcontacts, a holding coil 41,- and an operating coil 42. The holding coil41 is energized from the circuit and is controlled by the magnet switch27.

The operation of switch tOis similar to that of switch 26, except thatthe holding coil 41 restores or closesthe switch contacts after eachopening of the switch by the.opcrating coil 42 traversed by currentinduced in winding l3. .In the system in F ig. 6 the lag or inertiaeffect of the spring on switch 26, is obviated.

Normally the holding coil 41 maintains the switch contacts closed. \Vhenthe core of the hammer approaches. the air gap and the secondary winding13 of the hammer is energized to its maximum degree, the oper ating coil42 is energized to open the switch 40 against the pull of coil 41.. Themain hammer winding and, consequently, the secondary winding arede-energized. The

holding coil .41 immediately restores the ing and the core isreciprocated in synchrm hammer automatically"indicates theperinismow'ith the im pu'lsese The switch is thusautomaticallycontrolled-;to operate at :the proper instant/by theauxiliary hummer winding. Q

Iii-(Fig. -7 {is illustrated another modified systole-embodyingmywinvention. In this I system I employ aimeoh'an'ical vibrator 50 asthe switching device tomontroilthe circuit of. the. :mmn hammer winding.rllhe -v1bra- -.tor--5O comprises a-swdtc'h member 51, an o perating(c011 52,;a spring 53 and/a regulating coil-54. -i'zlhe. operating coil.52 is controlled udlirectly 'iby the trigger-"switch 23.

, :NVrhen ,the tri gier switch 23 is closed the (0 erat' vcoil 5 usienex ized'itrom an alter- -cnatingicu-rnent. circuit 55 and togetherwit h zithe. spring 5,34 effects synchronous viibrwti o n-1olf'theiswitclnmembe1' 51. The switch is thus '.-closedfoi' theduration soif waues of one poilanitxy; and isiqpien for (the duration ofwaves 50f: 2QPPOSit :polarity. The vibrator thus operates a's 1a'mec'h'anlical rectifier, t-l'ailliix-mittimg-gaill currentiamaves ofone apolzrrity but not waves of opposite polarityu'z-The ipolarityiofztihe iaransmitted waves will depend upon rthe polazrity of the firstwere idur ingivhich the switch member 51 is closed aiiter-o'losu're'ofthe (trigger switdh 23.

"The switchwmember 51 vibrates in synclammIi-sm wirth-the currenttraversing the operating COll:52,' 8iI)(1Jby adjustment of :the

spring 53 the travel of the switch =meun-ber a5l fma'y be ireducedtoia=minimum.

The switch willliopen and .close at instants corresponding to the. timelwhen the current va'lue iszero. 1 :Haviing once been adjusted,

the switch 5l will open and close when the value of tlhetcuriient theswitch operating coil becomes-zero, irrespective of conditionsin-ithe'circuilt of the hammer operating coil.

By reason of the 'varying inductance of -tl1e hammer operating-winding11, caused 'lbYhhQ movementofthe core 12, the current voltage as thecurrent traversing the switch =-operating winding 52. The-switch 51\Vlll traversing rthediammer'rwinding' will not have thesamephase-relation 'to the circuit therefore open when current traversesthe hammer operating winding circuit and arcinget the switch contactswill result.

By means of-the regulating switch coil 54,- however, iheopemtion of theswitch may be regulated in accordance'with ouriGO . or substantiallyzero.

rent conditions in the hammer winding or switch circuit. The operationof the switch may be accelerated or retarded depending upon the movementof the core ofthe. hammer. The switch may thus be controlled toopera-teat optimum current values when the current traversing the switchwill be zero The auxiliary winding 13 of the hammer is connected to theregulating coil 54 in such .manuer :that' the regnlatingcoil flux bucksor synol'rronism;

normal speed, the-rectifier switch opening 'or counteracts the flux ofthe uoperat-ing coil 52 of the vibrator or rectifier.

The auxiliary winding 13 on the hammer is energized in accordance withthe movement of the core in the hmnuner. \Vhen the core reaches themidpoint of its stroke, adjacent'the air gap between the \tipsof .thelaminations, the auxiliary windingattains its muxiui-um degree o fenergization. ;The

regulating coil 540i the rectifier 50 there upon eneng'izedkto--.counteract the holding eflectaoi the ;opemting .=c il ,52. and;th.e.con-

t acts aredisengaged to opeuthe circuit-of the main hammer winding. Pl..Hrhe core continues in its-movement, however, until it engages the tool18 or the springcushioned stop21=upon which it ex-pends the energystored :therein by the action of the operating coil.

i i I 41! Alternate current waves ure-transmittedto the main hammerwinding; by the rectifier to actuate the core member in ithe oneldirection or-the 'other', and the-core is permitted to continue itstravel after tl iecessation of each current wavezduningwthe intervalsbeg :twcen such current waves, to' exypendwits kinetic energy upon thetool or the ibackstogp.

' The core is thus rcoipnocated in 'synohronism with thetransmittedcurren-t :waves at frequency correspondin oi the circuitcurrent. 4

The oscillogram ini-Fig. zi8-:;il'lust-rates a typical wave form ofcurrent transmitted to the hummer-by the rectifier. 2 a r -The auxiliarywinding 13:0n hhehammer and the regulating -.w:i:nding 54 of therecti-'fier operate :to control the reotifier'sw itohel to increase 'or-todiminish the durationof cu-ch "current wave according to whether thecore lags or leads itswnormul speed.

core is thus hep-t instep *synchrbnism with the alternating cur rent inthe supply circuit, or with the unidirectional pulsations of-curre'nt inthe main hammer win'din'g. In case the corelwggor is retarded in itsoper-' .ation, the duration of-tl'recurrent wawe is extended to increasethe magnetic im pclling force on the core, audit-is brought into step Incase. the core 'leads'its is accelerated toj-diminish' the duration ofthe current wave and reduce the magnetic impelling force, to keep thecore in SyHClHO- v to :half the frequency the rectifier isnecessary toreduce the travel of the switch member and consequently, the

arcing. This does not mean that the conditions which cause arcing areeliminated, but merely that the extent of separation of the contacts islimited and that the arcing ocrurs between relatively close contactsurfaces. I Under suchconditions, it is ol course impossible to ,cut offthe circuit sharply because of the low resistance 01 the short are, andfor, that reason considerable energy stored'in the magnetic field of thehammer broadly a methodof controlling the .gnergi is dissipat ed in. theare as heat, with the consequent vdeter-ioration of the contactsurfaces. I l

"hea the ,auxiliary"windings are employed, ,however, the rectifier isautomati-j windings are used, the' 'arcing between the rectifier cont 51s therefore reduced to a. minimum, andt. iredeterioration of the.contact-Si precluded.

My invention, therefore,

com prehends zation of an elcctronn gnet in accordance with itsoperation, and means responsive to a condition'io'f the electromagnetfor con. t1.' o1ling an external switching device. Spe

.,;cific ally, my invention com 'n'ehends' a method of and means'forcont-rolling the open atioirof an electric hammer o'tthe reciprocatingmotor type by regulating or control ling a current transmitting ortranslating device in circuit with the hammer, in a'ccordancefwith-tlrepperation of the hammer itself."

Although I have shown several systems for controlling the operation ofan electric ha mmer of the reciprocating motor type. modifications maybe made therein by the substitution of other current transmitting orlrunglating Flori to control lilo hammer without departing from thespirit and scopeof my invention as set forth in the appended claims.

I claim as my invention-- l. The combination with a source of currentand a reciprocating motor energized therefrom comprising afield-producing winding and a magnctizable member actuated thereby withrespect to an air gap in the field produced by said winding, of anauxiliary winding inductively related to said first named winding, oneof said windings surrounding the other at substantially the region ofsaid air gap, means periodically delivering current from said source tosaid first named winding. and means controlled by the electro-niotive-force induced in said auxiliary winding controlling saidcurrent-delivering means.

2. The combination with a source of alterternatingj cor-dance with f thepositionmember for'iegiilat th'o (toil P, redetQlmifld nating currentandanpperating coil, :1 movable member controlled thereby: nd a rectilying device embodyingrelatively movable Contact members for suppl ingtothe oper ating coil predetermined portions of'the 'alternatingcurrent, of n eansresponsive to a" condition of the coil ir controllinnthe" operation of the rectifyin g'de vrc" i i0 6 viate between e e i ecgmlembcr ther'eofl' .3. The combinatio um ah noting current anope ablemember controlled th fyingf dev' .jcin bodying' 1 latn Iated to. i eiQberet the operatieniiof j tlier 4- Te. enema" nating can-mt and H 1.able memb r controlled nda'rect1fiymg deviceogembo'dyi iiiovablecontactmeniber' the a ting coil jp rectifying device.

5. Theconibr .o r natmg current eiatmgf coil a mo V1,; i 5' 5 ablemember cont! l led therebyand a'rectlf mg device ondzt ing' cur'ren iofa inductively related op at I influenced by m oy bleinern b forregulatingthe he rzefcti'f ngfdevicef 'Gl 'Th'e cdmliinati ori wrtli asotirceo'f alter nating current and a main operating coil, a movablemember controlled thereby, a rectifying device embodying relativelymovable contact members and an operating coil therefor for supplying tothe main operating coil predetermined portions of the alternatingcurrent, of a secondary coil inductively associated with the mainoperating coil, 21 secondary coil inductively associated with theoperating coil of the rectifying device, and means connecting bothsecondary coils in closed circuit relation.

7. The combination with a source of alternating current and an operatingcoil, a movable member controlled thereby and a rectifying deviceembodying relatively movable contact members for supplying to theoperating coil predetermined portions of thealternating current, and acoil for controlling said contacts, of a secondary coil inductivelyassociated with the main operating coil, and means controlled by thesecondary coil for controlling the rectifying device.

8. In a system for operating electric hammers, a source of alternatingcurrent, a solenoid, a core reciprocable thereby, a rectifier 1n e eaweuni rom zi di sdure rth "We. aid Wi ding an ux iary! w ndi g n ye ieted y,

I an, el'ectrq qnoti.

9. The combination with a source of hlterat n rre t. and. a; 'n z e ng.ote mpris g a n ti eldl a mg li eni t ndin r ene i i g th field; an

meme memh i nife el w h. sp t to said I I ir .gapfllength; Qfmeans e feting hvery f 'directidngrljmnulses of; current said st named .n p

d. meme ,m .e

9; flfhe' eqmhnw; 1.1]Wit 1,, ,.S 1; 'Q 1 eaming l s ntanfilj 'freciR ie ting motor ri ng emgee ee e lu W V l o e z whe. li lsliien ia ma n imber mo ed tthereby iof me'zinsiintei' vening b'emp ls s,them hr u msenf i g.

"force ,dfeRendent upon the uu' it n sa d. Wldifigjfildr hg o eme t f.1:-. megli tie ine e ifi' nd. m nn-Q t l theimnt se. po is t aid-i ltrb,

mo' y rr eme- '5 ,i

e' h e ing q g rent ndia Q e i e r said current impulses.

@slaid winding in r e'- said magnetic member, and means c0ntrol-' lingthe rectificetion'in' response to said electro motive forcel 12. Thecombination with a source of current and 1a reciprocating"motor,comprising a'niagnetie field having anhir gep, a Windineiiiher niovablerespect to said air gzip tojibsition, beyond I'minifnum' air gap cessiyeimpulses of currentfrom said source thro gh;SitldiW1i1d1ng,"a hux liarywinding located said 51 r ','iriductively affected said gfiis' named andsziid magnetic m jfln's' \v lth s'ai d h ux llia ry w nding I circuitcontrolling .T 3- iii. cem ii fii n {w ed me ternjatliig current and I hreci rocating motor, a field winding for sald motor 'anda magnet- I I III izable member moved thereby ofi inductive we alute-end $e1d= mada fmg. delivery of preponderatmgly uni-g irect onzrl men ns connected saiidsource ivhil'e' saidmotor is in operat on for controlling-the transmisson OfIliIiIdIIG QbmhflI current impulses iliery', winding; m uet it elyreliiftechto said field windingiand Ia clhpt ed. to react upon .said anclthei-ehy'modi'fjrtl1e,du-

r t-said if .'I have hereunto s mdn'y he-resubscribed lmy this; "day ofFebaiy, 92f EnWA-RDir:

MZISS-IEN;

